This paper presents some experimental and numerical results obtained on cement paste samples immersed in water with sulfate ions (15 mmol/l). Experimental results include the continuous monitoring of calcium loss and sulfate consumption within the cement paste, SEM, XRD and…
This paper presents some experimental and numerical results obtained on cement paste samples immersed in water with sulfate ions (15 mmol/l). Experimental results include the continuous monitoring of calcium loss and sulfate consumption within the cement paste, SEM, XRD and EDS analysis of the solid con- stituents of the cement matrix (Ettringite, Portlandite, Gypsum) within the leached (calcium depleted) thick- ness of the samples. Modeling of the combined diffusion transport problem with local equilibrium of the complex chemical system is then used to estimate the quantities of solid constituents which precipitates in the porous network during the external sulfate attack. The mechanical consequences (cracking) of ettringite or gypsum precipitation are then simulated via finite element analysis. The mechanical model is based on the or- thotropic damage theory and accounts for the chemo-mechanical couplings resulting from calcium leaching (chemical softening and damage).